P Block : Methods of Preparation
= Group 15 = Dinitrogen Commercial Method : 'Fractional distillation of liquid air . Liquid Dinitrogen boils out at 77.2 K and liquid oxygen boils out at 90 K . '''Laboratory Method : ' NH4Cl + NaNO2 ----------→ N2 + 2H2O + NaCl '''Other Methods : (NH4)2Cr2O7 + Heat ---------→ N2 + 4H2O + Cr2O3 3CaOCl2 + 2 NH3 ----------→ 3CaCl2 + 3H2O + N2 Ba(N3)2 + Heat ----------→ Ba + 3N2 2NaN3 + Heat -----------→ 2Na + 3N2 Ammonia Laboratory Method : ''' 2 NH4Cl + Ca(OH)2 + Heat ----------→ 2NH3 + CaCl2 + 2H2O '''Manufacturing Method : Haber Process N2 + 3H2 ----------→ 2NH3 It is a reversible process . Thus , equilibrium is shifted in the forward direction by using Le Chatellier's Principle . Temprature : 700 K ; Pressure = 200 x 105 Pa ; Catalyst : Al2O3 or K2O or Mb ; Promoter : Fe Other Methods : CaC2 + N2 + Heat ---------→ CaCN2 + C CaCN2 + H2O + Heat ----------→ CaCO3 + 2NH3 Nitric Acid Laboratory Method : NaNO3 + H2SO4 ----------→ NaHSO4 + HNO3 Large Scale Preparation : Ostwald Process 4NH3 + 5O2 -----500 K , 9 bar Pt/Rh gauge Catalyst---→ 4NO + 6H2O 2NO + O2 -------→ 2NO2 3NO2 + H2O ---------→ 2HNO3 + NO The efficiency of this method is 68% . By using H2SO4 , the efficiency can be increased to 98% . Phosphine Ca3P2 + 6H2O --------→ 3Ca(OH)2 + 2PH3 Ca3P2 + 6HCl ---------→ 3CaCl2 + 2PH3 2AlP + 3H2SO4 ---------→ Al2(SO4)3 + 2PH3 Laboratory Preparation : ''' P4 + 3NaOH + 3H2O ------→ PH3 + 3NaH2PO2 '''Other Methods : PH4I + KOH ------→ KI + PH3 + H2O Phosphorous Halides Phosphorous trichloride P4 + 6Cl2 --------------→ 4PCl3 + P4 + 8SOCl2 ------------→ 4PCl3 + 2S2Cl2 + 4SO2 Phosphorous pentachloride P4 + 10Cl2 ---------→ PCl5 P4 + 10SOCl2 ---------------→ 4PCl5 + 10 SO2 Oxyacids of Phosphorous = Group 16 = Dioxygen Commercial Method : ''' 1)Fractional distillation of liquid air . Liquid Dinitrogen boils out at 77.2 K and liquid oxygen boils out at 90 K . 2) Electrolysis of acidified water . '''General Methods : 2KClO3 + heat -------→ 2KCl + 3O2 2KNO3 + Heat --------→ 2KNO2 + O2 2KMnO4 + Heat ---------→ K2MnO4 + MnO2 + O2 2K2Cr2O7 + Heat --------→ 2K2O + 2Cr2O3 + 3O2 2KClO4 + Heat -------→ 2KCl + 4O2 2HgO + Heat -----720 K----→ 2Hg + O2 2Ag2O + Heat ----620 K----→ 4Ag + O2 2Pb3O4 + Heat --------→ 6PbO + O2 2PbO2 + Heat --------→ 2PbO + O2 2BaO2 + Heat --------→ 2BaO + O2 2H2O2 + Heat --------→ 2H2O + O2 6MnO2 + Heat --------→ 2Mn3O4 + 2O2 Laboratory Method : 2KClO3 --MnO2--420 K----→ 2KCl + 3O2 Other Methods 2Na2O2 + 2H2O --------→ 4NaOH + O2 2KMnO4 + 5Na2O2 + 8H2SO4 --------→ K2SO4 + 2MnSO4 + 5Na2SO4 + 8H2O + 5O2 Ozone Laboratory Method : 3O2 + electrical discharge --------→ 2O3 Sulphur dioxide Laboratoy Methods : ''' Cu + 2H2SO4 --------→ CuSO4 + SO2 + 2H2O Na2SO3 + 2HCl --------→ 2NaCl + H2O + SO2 '''Industrial Method : 4 FeS2 + 11O2 --------→ 2Fe2O3 + 8SO2 Other Methods : S + O2 --------→ SO2 Sulphuric Acid Contact Process Lead Chamber Process = Group 17 = Chlorine General Methods : MnO2 + 4HCl + Heat --------→ MnCl2 + Cl2 + 2H2O PbO2 + 4HCl --------→ PbCl2 Pb3O4 + 8HCl --------→ 3PbCl2 + Cl2 + 4 H2O 2KMnO4 + 16HCl + --------→ 2KCl + Cl2 + 4H2O 2KMnO4 + 14HCl --------→ 2KCl + 2CrCl3 + 3Cl2 + 7H2O CaOCl2 +2HCl --------→ CaCl2 + Cl2 + H2O CaOCl2 + H2SO4 --------→ CaSO4 + Cl2 + H2O 2NaCl + MnO2 + 3H2SO4 --------→ CaSO4 + Cl2 + 2H2O Manufacturing Methods : 'Deacon Process : ' 4HCl + O2 ----CuCl2----→ 2Cl2 + H2O '''Electrolytic Process : '''Electrolysis of aqueous solution of NaCl . Cl2 and H2 are librated , while NaOH is left behind in the solution . Hydrochloric Acid NaCl + H2SO4 -----420 K---→ HCL + NaHSO4 NaHSO4 + NaCl -----823 K---→Na2SO4 + HCl Interhalogen Compounds = Group 18 = No Methods of Preparation